In all isolation methods, we found no significant difference in the in vitro activity of LRRK2 purified from PBMCs from iPD patients in comparison to control subjects (Protocol B; Fig. 1A), suggesting that LRRK2 in these cells does not undergo any modifications in the context of PD that alter its intrinsic kinase activity. The gene discussed is LRRK2; the disease is Parkinson disease.